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排序方式: 共有465条查询结果,搜索用时 343 毫秒
1.
介绍一种以89C51为核心,通过AD和LED,实现光电经纬仪摄影机目标距离显示的方法。该方法提出了一些新的设计方案,从而使整个系统结构简单,运行可靠。 相似文献
2.
Statistical analysis of sand grain/bed collision process recorded by high-speed digital camera 总被引:1,自引:0,他引:1
A high‐speed digital camera was employed to record the sand grain/bed collision process. With image processing and a statistical method, a series of parameters of the collision process were obtained. The results show that the collision process of a grain with rebounding can be represented by two parameters: the kinetic energy restitution coefficient and the collision angle. Both parameters satisfy a normal distribution, and they are dependent on one another. With an increase of the collision angle, the distribution of the kinetic energy restitution gradually reduces from a broad to a narrow range with low values. The percentage of vertical velocity restitution coefficients greater than 1 can reach 70% or more, which ensures that the settling time of the sand grains in the air increases and that they receive more energy from the air to progress the saltation movement. 相似文献
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简要分析了非量测数码相机哈苏H1D在南极中山站及拉斯曼丘陵地区所获取的影像数据的几何精度,阐明了利用该影像数据进行空中三角测量,DLG,DOM制作的技术流程及作业过程中出现问题的处理方法。 相似文献
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Monitoring of Over Cutting Area and Lubrication Distribution in a Large Slurry Pipe Jacking Operation 总被引:1,自引:0,他引:1
Saeid Khazaei Hideki Shimada Takashi Kawai Junichi Yotsumoto Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(3):735-755
Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines
of sewage systems. Pipe jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and
other projects. Basically the system involves the pushing or thrusting of concrete pipes into the ground by a number of jacks.
In slurry pipe jacking, during the pushing process, mud slurry and lubricant are injected into the face and the over cutting
area that is between the concrete pipes and the surrounding soil. Next, the slurry fills voids and the soil stabilizes due
to the created slurry cake around the pipes. Fillings also reduce the jacking force or thrust during operation. When the drivage
and pushing processes are finished, a mortar injection into the over cutting area is carried out in order to maintain permanent
stability of the surrounding soil and the over cutting area. Successful lubrication around the pipes is extremely important
in a large diameter slurry pipe jacking operation.
Control of lubrication and gaps between pipes and soil can prevent hazards such as surface settlement and increases in thrust.
Also, to find voids around the pipes after the jacking process, in order to inject mortar for permanent stabilizing, an investigation
around the pipes is necessary. To meet these aims, this paper is concerned with the utilization of known methods such as the
GPR (Ground Penetrating Radar) system and borehole camera to maintain control of the over cutting area and lubricant distribution
around the pipes during a site investigation. From this point of view, experiments were carried out during a tunnel construction
using one of the largest cases of slurry pipe jacking in Fujisawa city, Japan. The advantages and disadvantages of each system
were clarified during the tests. 相似文献
7.
大型高速滑坡滑动过程中碰撞特性的试验 总被引:1,自引:1,他引:1
首次提出了滑坡岩体高速碰撞模型实验方法。通过实验,研究了滑体碰撞解体后不同速度段岩体体积的分布规律,得出了加速块体所占比例基本与滑体体积及碰撞速度无关,而个别块体获得的加速效应与滑坡体积及碰撞速度有明显的正相关关系。 相似文献
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对比总体最小二乘方法与最小二乘方法在相机标定中的适用性及优越性。在相机标定中,由于像点坐标和对应的地面点坐标均存在误差,因此采用总体最小二乘方法对误差方程中的系数矩阵及观测向量同时改正,能够建立更加合理的计算模型。文中以相机标定两步法为例,通过实例解算,证明利用总体最小二乘法能够得到精度更高的相机标定参数解。 相似文献
10.